JP2014193939A - Highly weather-resistant adhesive composition and adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which may be used for adhesion of films and the like and an adhesive film, which are used in an environment such that the film is exposed to electromagnetic waves which includes ultraviolet light such as sunlight for a long period, the adhesive composition and the adhesive film having excellent weather resistance and being capable of drastically suppressing a change in color taste even if exposed to ultraviolet light for a long period.SOLUTION: The adhesive composition comprises an adhesive mass, an ultraviolet absorber, and a hindered phenolic antioxidant. The hindered phenolic antioxidant includes at least one selected from the group consisting of triazine skeleton compounds, thio skeleton compounds, and cresol skeleton compounds.

Description

  The present invention relates to a pressure-sensitive adhesive composition having high weather resistance used for bonding to a transparent substrate and a pressure-sensitive adhesive film using the pressure-sensitive adhesive composition.

  In recent years, some window glass of buildings and vehicles has a window film bonded for the purpose of shielding heat rays or preventing scattering. Moreover, the functional film for providing a heat ray shielding function etc. may be bonded also to the optical lens used for aggregation of light and diffusion. These window films and functional films are usually bonded to an adherend (for example, window glass) via an adhesive. Therefore, it is necessary to use the adhesive excellent in transparency so that transmission of light may not be impaired for the adhesive used for bonding.

  When used in an environment exposed to sunlight for a long time, the pressure-sensitive adhesive used in the above-described applications may be gradually colored due to deterioration over time due to ultraviolet rays or the like, although it was initially transparent. is there. For this reason, there is a demand for a pressure-sensitive adhesive that has not only high transparency but also excellent weather resistance such that the color change due to aging is as small as possible. For example, Japanese Patent Application Laid-Open No. 2008-200903 (Patent Document 1) discloses an infrared absorption film in which an infrared absorption layer is formed on one side of a base film and an adhesive layer is formed on the other side. It has been proposed that the agent layer may contain an ultraviolet absorber, an antioxidant or the like as required.

  In JP 2008-248131 A (Patent Document 2), a (meth) acrylic ester copolymer having a carboxyl group as a crosslinkable functional group, a metal chelate crosslinking agent, and a triazine ultraviolet absorber. The adhesive for solar radiation shielding films containing these is disclosed.

JP 2008-200903 A JP 2008-248131 A

  The inventors of the present invention have been exposed to electromagnetic waves containing ultraviolet rays such as sunlight for a long period of time by using a UV absorber and a specific hindered phenolic antioxidant in combination with the adhesive. Also obtained the knowledge that the color change of the pressure-sensitive adhesive can be remarkably suppressed. The present invention is based on this finding.

  Accordingly, an object of the present invention is a pressure-sensitive adhesive composition used for bonding films and the like used in an environment that is exposed to an electromagnetic wave containing ultraviolet rays such as sunlight for a long period of time. It is to provide a pressure-sensitive adhesive composition excellent in weather resistance that can remarkably suppress color change even when exposed to a period.

  Another object of the present invention is to provide a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition having excellent weather resistance as described above.

According to one aspect of the invention,
With adhesive,
With UV absorbers,
A pressure-sensitive adhesive composition comprising a hindered phenol-based antioxidant,
There is provided a pressure-sensitive adhesive composition, wherein the hindered phenol-based antioxidant comprises at least one selected from the group consisting of a triazine skeleton, a thio skeleton, and a cresol skeleton.

According to another aspect of the present invention,
There is provided a pressure-sensitive adhesive film comprising at least one substrate and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition of the present invention.

According to yet another aspect of the present invention,
A pressure-sensitive adhesive film obtained by laminating a first release paper, a pressure-sensitive adhesive layer, and a second release paper in this order, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition of the present invention. A film is provided.

  According to the present invention, by using an ultraviolet absorber in combination with a specific hindered phenol-based antioxidant, the color of the pressure-sensitive adhesive even when exposed to electromagnetic waves containing ultraviolet rays such as sunlight for a long period of time. The change can be remarkably suppressed.

[Adhesive composition]
The pressure-sensitive adhesive composition according to the present invention includes a pressure-sensitive adhesive, an ultraviolet absorber, and a hindered phenol-based antioxidant containing at least one of a triazine skeleton, a thio skeleton, and a cresol skeleton as its constituent components. The pressure-sensitive adhesive composition according to the present invention preferably further contains a crosslinking agent. Each component will be described below.

<Adhesive>
For the pressure-sensitive adhesive according to the present invention, an acrylic copolymer is mainly used. The acrylic copolymer is obtained by copolymerizing a monomer containing a monomer unit having a carboxyl group or a hydroxyl group as a monomer unit. The monomer unit having a carboxyl group includes acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, succinic acid monohydroxyethyl (meth) acrylate, maleic acid mono Hydroxyethyl (meth) acrylate, monohydroxyethyl fumarate (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth) acrylate, (meth) acrylic acid dimer, ω -Carboxy-polycaprolactone mono (meth) acrylate and the like. One or more of these carboxyl group-containing (meth) acrylate monomers may be contained. In addition, in this specification, (meth) acrylic acid shall mean acrylic acid and / or methacrylic acid.

  The above-mentioned acrylic copolymer may contain other monomer units. For example, a (meth) acrylic acid ester can be preferably used. Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, and n-octyl (meta ) Acrylate, i-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, i-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate Stearyl (meth) acrylate and the like can be used. These acrylic acid esters may contain 1 type (s) or 2 or more types.

  The above carboxyl group-containing (meth) acrylate can be added to the (meth) acrylic acid ester in consideration of the adhesiveness and reworkability of the acrylic pressure-sensitive adhesive. It is preferable to add 0.1 to 10% of a carboxyl group-containing (meth) acrylate monomer on a mass basis with respect to the (meth) acrylic acid ester monomer unit with respect to the (meth) acrylic acid ester monomer unit.

  The acrylic copolymer used in the present invention may contain a hydroxyl group-containing (meth) acrylate as an arbitrary monomer unit in addition to the above (meth) acrylic acid ester. Examples of the hydroxyl group-containing (meth) acrylate include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate. , 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-methyl-3-hydroxybutyl (meth) acrylate, 1,1-dimethyl-3-butyl (meth) acrylate, 1,3- Dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl-3-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, polypro Glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol - propylene glycol) mono (meth) acrylate, N- methylol acrylamide, allyl alcohol, methallyl alcohol and the like. One or more of these hydroxyl group-containing (meth) acrylates may be contained. Among the hydroxyl group-containing (meth) acrylates as described above, alkoxyalkyl (meth) acrylates can be preferably used. By including these hydroxyl group-containing (meth) acrylates, the glass transition temperature is increased, and the pressure-sensitive adhesive composition is obtained. Since the coating film when applied can be hardened, the reworkability of the acrylic pressure-sensitive adhesive can be improved.

  The hydroxyl group-containing (meth) acrylate described above can be added to the (meth) acrylic acid ester in consideration of the adhesiveness and reworkability of the acrylic pressure-sensitive adhesive. It is preferable to add 10 to 75% of a hydroxyl group-containing (meth) acrylate monomer on a mass basis with respect to the (meth) acrylic acid ester monomer.

  In the present invention, in addition to the monomer units described above, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, glycidyl (meth) are appropriately used. Glycidyl group-containing (meth) acrylate monomers such as allyl ether, 3,4-epoxycyclohexyl (meth) allyl ether, acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N -Methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butylacrylamide, - octylacrylamide, may be included containing amide groups of diacetone acrylamide (meth) acrylate monomer.

  The acrylic copolymer used in the present invention can be obtained by polymerizing the above monomer unit by a method such as ordinary solution polymerization, bulk polymerization, emulsion polymerization or suspension polymerization. It is preferable to produce by copolymerization in which the copolymer is obtained as a solution. By obtaining the acrylic copolymer as a solution, it can be used as it is for producing the pressure-sensitive adhesive composition of the present invention.

  Examples of the solvent used for the solution polymerization include organic solvents such as ethyl acetate, toluene, n-hexane, acetone, and methyl ethyl ketone. Examples of the polymerization initiator used in the polymerization include peroxides such as benzoyl peroxide and lauryl peroxide, azobis compounds such as azobisisobutyronitrile and azobisvaleronitrile, and polymer azo polymerization initiators. These can be used alone or in combination. Moreover, in the said superposition | polymerization, in order to adjust the molecular weight of an acryl-type copolymer, a conventionally well-known chain transfer agent can be used.

  The mass average molecular weight of the acrylic copolymer used in the present invention is not particularly limited, but is preferably in the range of 300,000 to 1,500,000, and in the range of 600,000 to 1,000,000 from the viewpoint of durability. It is more preferable that The mass average molecular weight can be measured by GPC (gel permeation chromatography) using a polystyrene standard sample. As the acrylic pressure-sensitive adhesive as described above, commercially available ones may be used. For example, SK dyne 2094, SK dyne 2147, SK dyne 1811L, SK dyne 1415, etc., manufactured by Soken Chemical Co., Ltd. are preferably used. Can do.

<Ultraviolet absorber>
Examples of UV absorbers include triazine UV absorbers, benzophenone UV absorbers, and benzotriazole UV absorbers. Triazine UV absorbers are compatible from the viewpoint of compatibility with acrylic copolymers and weather resistance. Agents are particularly preferred.

  Examples of the triazine ultraviolet absorber include 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4- Bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3-tridecyloxypropyl) Oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, and 2- [4-[(2-hydroxy-3- (2′-ethyl) F) Xyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine and the like, and commercially available triazine ultraviolet absorbers include BASF. TINUVIN 400, TINUVIN 405, TINUVIN 460, TINUVIN 477, TINUVIN 479 and the like sold by the company.

  Examples of the benzophenone ultraviolet absorber include 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2 -Hydroxy-4-methoxybenzophenone, hydroxymethoxybenzophenonesulfonic acid and its trihydrate, hydroxymethoxybenzophenone sodium sulfonate, and the like, and commercially available benzophenone-based UV absorbers include CHMASSORB81 sold by BASF / FL and the like.

  Examples of the benzotriazole ultraviolet absorber include 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate, 2- (2H -Benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- ( tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- ( 2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert- Til-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-) (3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6 -(2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, and the like are commercially available. The benzotriazole UV absorbers available are TINUVIN PS, TINUVIN 99-2, TINUVIN sold by BASF 84-2, and a TINUVIN900, TINUVIN928, TINUVIN1130 like.

<Antioxidant>
The antioxidant according to the present invention is a hindered phenol-based antioxidant, and includes at least one selected from the group consisting of a triazine skeleton, a thio skeleton, and a cresol skeleton. Here, the hindered phenol-based antioxidant is an antioxidant having a phenol structure in the skeleton of the antioxidant compound and having a bulky substituent near the hydroxyl group in the phenol structure. An agent. For example, an antioxidant having at least one tert-butyl group next to a hydroxyl group as a bulky substituent is preferred.

  In the present invention, the triazine skeleton refers to a 6-membered ring structure containing three nitrogen atoms, and is composed of any of 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine. A cyclic structure may be sufficient and a saturated cyclic structure may be sufficient.

  In the present invention, the thio skeleton refers to a structure having a sulfur atom. When the hindered phenol-based antioxidant has a thio skeleton, the sulfur atom may be contained in the structure of the antioxidant compound in either a saturated bond or an unsaturated bond, and in the form of a cyclic structure. It may be included.

  In the present invention, the cresol skeleton refers to a structure in which any hydrogen atom existing on the benzene ring of toluene is substituted with a hydroxyl group, and is any structure of o-cresol, m-cresol, and p-cresol. Alternatively, any of other hydrogens present on the benzene ring of toluene may be further substituted with another substituent. In addition, when the hindered phenol-based antioxidant has a cresol skeleton, it may constitute a hindered phenol structure by having a bulky substituent near the hydroxyl group of cresol, and has a hindered phenol structure. Any one of the aromatic 6-membered hydrogen atoms may be substituted and bonded to cresol.

  As the antioxidant that is a hindered phenol-based antioxidant and includes at least one selected from the group consisting of a triazine skeleton, a thio skeleton, and a cresol skeleton, various compounds can be used. 2,2-thio [diethylbis-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (dodecylthiomethyl) -6-methylphenol, 2,4-bis ( Octylthiomethyl) -6-methylphenol, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 6- (4-hydroxy-3,5-di-tert-butylanilino) -2, Examples include 4-bis (octylthio) -1,3,5-triazine, but are not limited thereto. As the above-mentioned antioxidant, commercially available products may be used. For example, IRGANOX 1035, IRGANOX 1726, IRGANOX 1520L, IRGANOX 3114, IRGANOX 565, etc. manufactured by BASF, Sumitizer WX-R, SUMILIZER WX- manufactured by Sumitomo Chemical Co., Ltd. RC or the like can be suitably used.

  The content of the antioxidant may be 10 parts by mass or less in solid ratio with respect to 100 parts by mass of the adhesive used in the adhesive composition, and coloring due to deterioration of the antioxidant itself can be suppressed. It is preferable at a point, It is more preferable that it is 7.5 mass parts or less, It is most preferable that it is 5.0 mass parts or less.

  By blending the above-mentioned antioxidant with an adhesive and UV absorber to form an adhesive composition, high weather resistance can be imparted that can significantly suppress color changes when exposed to sunlight for a long period of time. can do. Without being bound by theory, the above-mentioned specific antioxidant is combined with a pressure-sensitive adhesive and a UV absorber to form a pressure-sensitive adhesive composition, thereby increasing the generation of floating radicals in the pressure-sensitive adhesive composition during irradiation. It is assumed that it can be suppressed with accuracy and can satisfy the performance of capturing the generated radicals.

The pressure-sensitive adhesive composition according to the present invention has high weather resistance that can remarkably suppress color change when exposed to electromagnetic waves containing ultraviolet rays such as sunlight for a long period of time. The degree of change in color (Δb ^* ) after the sunshine carbon arc test in accordance with JIS 5759 is required to be less than 0.7. Here, the degree of color change (Δb ^* ) represents the amount of change in chromaticity (b ^* ) in the L ^* a ^* b ^* color system before and after the test, and the degree of color change (Δb ^* ). A larger value means that the yellow color increases after the test.

Further, it is possible that the lightness change degree (ΔL ^* ) before and after the sunshine carbon arc test according to JIS 5759 is within ± 0.25 and the color change degree (Δa ^* ) is within ± 0.40. It is preferable from the viewpoint. Further, when expressed in the xyY color system, the chromaticity change degrees (Δx and Δy) are preferably within ± 0.0010 and within ± 0.0015, respectively, from the viewpoint of weather resistance.

  The haze value and total light transmittance are also preferably not significantly changed before and after the sunshine carbon arc test, the haze change (ΔHz) is preferably less than 2.00, and the total light transmittance change (ΔTT) is less than 0.40. Is preferred.

  Moreover, when bonding a transparent base material (glass or plastic) and a to-be-adhered body, it is preferable that a haze value is 3.0% or less so that transparency of a transparent base may not be impaired. The light transmittance is preferably 85% or more.

<Crosslinking agent>
The pressure-sensitive adhesive composition according to the present invention may contain a crosslinking agent. By adding a crosslinking agent, stickiness can be improved while maintaining the adhesive strength. Various crosslinking agents can be used, and examples thereof include an epoxy crosslinking agent and an isocyanate crosslinking agent. In the present invention, it is preferable to use an epoxy-based crosslinking agent in order to suppress a change in chromaticity. Examples of the epoxy-based crosslinking agent include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether. 1, 6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polybutadiene diglycidyl ether, and the like. These epoxy-based crosslinking agents may be included in one kind or two or more kinds.

  As an isocyanate type crosslinking agent, for example, a polyisocyanate compound, a trimer of a polyisocyanate compound, a urethane prepolymer having a terminal isocyanate group obtained by reacting a polyisocyanate compound and a polyol compound, 3 of the urethane prepolymer Examples include a polymer. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 3 -Methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate and the like.

  The content of the crosslinking agent can be appropriately adjusted in consideration of the adhesive strength and reworkability of the pressure-sensitive adhesive. For example, 0.001 to 10 parts by mass in solid ratio with respect to 100 parts by mass of the acrylic copolymer It is preferable to set it as 0.01-1 mass part.

<Other ingredients>
In addition, the pressure-sensitive adhesive composition may include, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slip properties, mold release properties, flame retardancy, antifungal properties. For the purpose of improving and modifying properties, electrical properties, strength, etc., for example, lubricants, plasticizers, fillers, fillers, antistatic agents, antiblocking agents, crosslinking agents, light stabilizers, dyes, pigments, etc. Other colorants, etc. may be added. Further, if necessary, a coupling agent such as silane, titanium, and aluminum can be further included.

  The pressure-sensitive adhesive composition according to the present invention can be prepared by mixing the above-described components and kneading and dispersing as necessary. The mixing or dispersing method is not particularly limited, and a usual kneading and dispersing machine such as a two-roll mill, a three-roll mill, a pebble mill, a tron mill, a Szegvari attritor, a high-speed impeller disperser, a high-speed stone mill, A high speed impact mill, a desper, a high speed mixer, a ribbon blender, a kneader, an intensive mixer, a tumbler, a blender, a desperser, a homogenizer, an ultrasonic disperser, and the like can be applied. In addition, in order to adjust the viscosity of the pressure-sensitive adhesive coating solution, a diluent solvent may be added to mix each component.

[Adhesive film]
The pressure-sensitive adhesive film according to the present invention is formed by laminating the form of a pressure-sensitive adhesive film comprising at least one base material and a pressure-sensitive adhesive layer, the first release paper, the pressure-sensitive adhesive layer, and the second release paper in this order. The form of the double-sided adhesive film comprised by this may be sufficient. In this specification, “film” includes sheets and tapes.

  Although the thickness of the adhesive film by this invention changes also with uses, it is about 10 micrometers-about 300 micrometers normally, Preferably it is 10 micrometers-200 micrometers. Moreover, although the thickness of the adhesion layer can also be selected suitably, it is preferable that they are 5 micrometers-200 micrometers, and it is more preferable that they are 10 micrometers-100 micrometers. If it is in the said range, the influence on the optical characteristic of a base material or a to-be-adhered body can be suppressed.

  The method of applying the pressure-sensitive adhesive composition to the substrate or release paper is not particularly limited. For example, roll coating, reverse roll coating, transfer roll coating, gravure coating, gravure reverse coating, comma coating, rod coating Blade coating, bar coating, wire bar coating, die coating, lip coating, dip coating, etc. can be applied.

<Base material>
It is preferable that the base material used for the adhesive film by this invention is transparent. Here, the transparent does not necessarily need to be colorless and transparent, and may be colored and transparent, but the total light transmittance is preferably 80% or more, and more preferably 85% or more. .

  The base material used for the pressure-sensitive adhesive film according to the present invention is not particularly limited as long as it has the above-described light transmittance, required strength, and flexibility, and can be appropriately selected. Generally, a synthetic resin film is used. Synthetic resin film materials include polyester resins, polypropylene resins, polyvinyl chloride resins, fluorine resins, polystyrene resins, poly (meth) acrylic resins, cellulose resins, polycarbonate resins, polyamide resins, Known resins such as polyolefin resins, polyvinyl alcohol resins, polyimide resins, phenolic resins, polyurethane resins and the like can be mentioned. These can be used alone or in combination of two or more. Moreover, a single layer may be sufficient and the laminated body of two or more layers may be sufficient. From the viewpoint of mechanical strength, a uniaxially stretched or biaxially stretched film is preferred. In the present invention, among the synthetic resins, it is particularly preferable to use a polyester-based resin or a polycarbonate-based resin from the viewpoints of transparency, heat resistance, dimensional stability, rigidity, flexibility, suitability for stacking, price, and the like.

  Examples of the polyester-based resin include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyarylate, polytetramethylene terephthalate, etc. Among them, from the viewpoint of ease of handling, low cost, etc. Polyethylene terephthalate is particularly preferred.

  The thickness of a base material is not specifically limited, According to a use, it can select suitably. Usually, it is about 10-200 micrometers, Preferably it is 20-175 micrometers.

  The formation method of a base material is not specifically limited, For example, conventionally well-known film forming methods, such as a solution casting method, a melt extrusion method, and a calender method, can be used. Moreover, you may use the commercially available base material previously formed into a film form by the said method.

  In addition, in order to improve the wettability with the adhesive on the base material, corona discharge treatment, plasma treatment, ozone treatment, flame treatment, primer treatment, preheat treatment, dust removal treatment, vapor deposition treatment on one side or both sides. Further, known easy adhesion treatment such as alkali treatment may be performed.

<Release paper>
In the pressure-sensitive adhesive film according to the present invention, a release paper may be provided on one or both sides of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. In the pressure-sensitive adhesive film of the present invention, the release paper is made of a material having releasability, has a function of protecting the surface of the pressure-sensitive adhesive layer, and is peeled and removed during use. The release paper is not particularly limited as long as it has the required strength and flexibility. For example, a film made of a resin such as polyethylene terephthalate, polypropylene, or polyethylene or a foamed film thereof may be silicone-based, fluorine-based, long Examples thereof include those subjected to release treatment with a release agent such as a chain alkyl group-containing carbamate. Although the thickness of a release paper is not specifically limited, Preferably it is 12-100 micrometers.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by an Example.

Example 1
<Preparation of pressure-sensitive adhesive composition>
An epoxy-based cross-linking agent (product name “E-5XM” with respect to 100 parts by mass of an acrylic adhesive main agent (product name “SK Dyne 2094”, weight average molecular weight: 800,000, solid content: 25%, manufactured by Soken Chemical Co., Ltd.) ”, Solid content: 5%, manufactured by Soken Chemical Co., Ltd.) with a solid ratio of 0.054 parts by mass, and triazine-based ultraviolet absorber (product name“ TINUVIN477 ”, solid content 80%, manufactured by BASF) with a solid ratio of 8 0.0 part by mass and 1.0 part by mass of a hindered phenol antioxidant (IRGANOX 1035, Mw: 643, nv: 100%, manufactured by BASF) having a thio skeleton of the following chemical formula 1 in a solid ratio Thus, a pressure-sensitive adhesive composition was obtained.

  The obtained pressure-sensitive adhesive composition was applied on a 38 μm-thick PET carrier film (product name POL382150, manufactured by Lintec Co., Ltd.) subjected to silicone peeling treatment using an applicator so that the thickness when dried was 25 μm. The pressure-sensitive adhesive layer was formed by drying at 100 ° C. for 2 minutes. A 38 μm-thick PET carrier film (product name POL 381031, manufactured by Lintec Co., Ltd.) subjected to silicone peeling treatment was bonded to the pressure-sensitive adhesive layer surface, and aged for 1 week at normal humidity and room temperature to obtain a pressure-sensitive adhesive film.

Example 2
A hindered phenol antioxidant (IRGANOX1520L, Mw: 424.7, nv: 100%, manufactured by BASF) having a thio skeleton and a cresol skeleton of the following chemical formula 2 was used in place of the antioxidant of chemical formula 1. Produced a film in the same manner as in Example 1.

Example 3
Example 1 except that a hindered phenol antioxidant (IRGANOX 3114, Mw: 784, nv: 100%, manufactured by BASF) having a triazine skeleton of the following chemical formula 3 was used in place of the antioxidant of chemical formula 1. A film was prepared in the same manner.

Comparative Example 1
A film was prepared in the same manner as in Example 1 except that the antioxidant was not added.

Comparative Example 2
A film was prepared in the same manner as in Example 1 except that a hindered amine antioxidant of the following chemical formula 4 (TINUVIN123, Mw: 737, nv: 100%, manufactured by BASF) was used instead of the antioxidant of the chemical formula 1. .

Comparative Example 3
Example 1 except that a hindered amine antioxidant having a hindered phenol skeleton of the following chemical formula 5 (TINUVIN 144, Mw: 685, nv: 100%, manufactured by BASF) was used instead of the antioxidant of the chemical formula 1. A film was prepared in the same manner.

Comparative Example 4
Example 1 except that a hindered amine antioxidant having a triazine skeleton of the following chemical formula 6 (TINUVIN 152, Mw: 756.6, nv: 100%, manufactured by BASF) was used instead of the antioxidant of the chemical formula 1. A film was prepared in the same manner.

Comparative Example 5
Example 1 except that a hindered amine antioxidant of the following chemical formula 7 (TINUVIN292, Mw: 508.8 and 369.6, nv: 100%, manufactured by BASF) was used in place of the antioxidant of the chemical formula 1. A film was prepared in the same manner.

Comparative Example 6
A film was prepared in the same manner as in Example 1 except that a hindered phenol antioxidant (IRGANOX 1010, Mw: 1178, nv: 100%, manufactured by BASF) of the following chemical formula 8 was used in place of the antioxidant of chemical formula 1. Created.

Comparative Example 7
Example 1 except that a hindered amine antioxidant (CHIMASSORB2020FDL, Mw: 2600-3400, nv: 100%, manufactured by BASF) having a triazine skeleton of the following chemical formula 9 was used instead of the antioxidant of chemical formula 1. Similarly, when the pressure-sensitive adhesive composition was prepared, the film could not be formed because the pressure-sensitive adhesive composition gelled when the antioxidant was added.

Comparative Example 8
A film was prepared in the same manner as in Example 1 except that a hindered amine antioxidant of the following chemical formula 10 (TINUVIN 770DF, Mw: 481, nv: 100%, manufactured by BASF) was used instead of the antioxidant of the chemical formula 1. .

Comparative Example 9
Example 1 except that a hindered amine antioxidant (CHIMASSORB944FDL, Mw: 2000 to 3100, nv: 100%, manufactured by BASF) having a triazine skeleton of the following chemical formula 10 was used in place of the antioxidant of chemical formula 1. Similarly, when the pressure-sensitive adhesive composition was prepared, the film could not be formed because the pressure-sensitive adhesive composition gelled when the antioxidant was added.

The chemical structures of the antioxidants used in Examples 1 to 3 and Comparative Examples 1 to 9 are summarized in Table 1 below.

<Evaluation of adhesive film>
Each of the adhesive films obtained in Examples 1 to 3 and Comparative Examples 1 to 6 and 8 was cut into two sets each having a size of 25 mm × 70 mm, and a single-sided PET carrier film (product name POL 381031, manufactured by Lintec) was peeled off. The pressure-sensitive adhesive surface was bonded to a slide glass (manufactured by Matsunami Glass Kogyo Co., Ltd., water slide glass S7213 Preclin water edge polish, size: 26 mm × 76 mm, thickness: 0.9 to 1.2 mm) using a rubber roller.

  One sample of the two cut out sets was peeled off the PET carrier film (product name POL382150, manufactured by Lintec) on the other side, and then applied to the easy-adhesive surface of the PET film (Cosmo Shine A4100, 100 um, manufactured by Toyobo). Bonding was performed using a rubber roller, and the initial chromaticity, total light transmittance, and haze were measured.

  Of the two sets cut out, the other sample was taken out after being put into a weather resistance tester (according to Sunshine Carbon Arc / JIS 5759) for a predetermined time, and then removed from the other side of the PET carrier film (product name POL382150, manufactured by Lintec). ), And then bonded to an easy-adhesive surface of a PET film (A4100, 100 um, manufactured by Toyobo Co., Ltd.) using a rubber roller, and the chromaticity, total light transmittance and haze after the weather resistance test are measured, and the weather resistance Changes before and after the test were evaluated.

<Weather resistance test>
The weather resistance test was performed using a sunshine carbon arc in accordance with JIS5759. At that time, the samples were set on the tester in the order of the light source / slide glass / adhesive layer / PET film. Details of the test conditions are shown below.
・ Test input time: 2000h
-One sunshine carbon arc lamp-Optical filter Spectral transmittance: 2% or less at 275 nm, 90% or more at 400 nm-Black panel temperature: 63 ° C, relative humidity: 50 ± 5%, irradiance on the specimen surface 255 ± 10% W / m2 (300 ~ 700nm)
・ Water injection: Water injection for 18 minutes in 120 minutes

<Chromaticity / lightness measurement>
Chromaticity and lightness measurement before and after the weather resistance test of the sample is performed using a measurement method based on JIS Z8722 (measurement method: transmission, measurement light source: C light source, field of view: 2 °) using SD-5000 manufactured by Nippon Denshoku Co. I went there.

<Measurement of haze and total light transmittance>
For haze and total light transmittance, NDH2000 manufactured by Nippon Denshoku was used to measure the haze value (based on JIS-K7136) and the total light transmittance (based on JIS-K7361).

About the said Examples 1-3 and Comparative Examples 1-6 and 8, the optical physical-property value before and after a weather resistance test (haze (Hz), total light transmittance (TT), and chromaticity and lightness (x, y, L ^* , The results of measuring a ^* , b ^* )) are shown in Tables 2 to 4 below.

  Subsequently, Examples 1 to 3 were tested by changing the amount of the antioxidant. Details are shown below.

Example 4
Example except that the blending amount of the hindered phenol antioxidant (IRGANOX 1035, Mw: 643, nv: 100%, manufactured by BASF) having the thio skeleton of Chemical Formula 1 was changed to 2.5 parts by mass in solid ratio A film was prepared as in 1.

Example 5
Example except that the blending amount of the hindered phenol antioxidant (IRGANOX 3114, Mw: 784, nv: 100%, manufactured by BASF) having a triazine skeleton of Formula 3 was changed to 2.5 parts by mass in solid ratio A film was prepared as in 3.

Example 6
Example except that the amount of hindered phenol antioxidant (IRGANOX 3114, Mw: 784, nv: 100%, manufactured by BASF) having a triazine skeleton of Formula 3 was changed to 5.0 parts by mass in solid ratio A film was prepared as in 5.

About the adhesive film obtained in the said Examples 4-6, it evaluated similarly to Examples 1-3. The optical property values (haze (Hz), total light transmittance (TT), chromaticity and lightness (x, y, L ^* , a ^* , b ^* )) before and after the weather resistance test were measured. Shown in ~ 7.

Claims (9)

With adhesive,
With UV absorbers,
A pressure-sensitive adhesive composition comprising a hindered phenol-based antioxidant,
The pressure-sensitive adhesive composition, wherein the hindered phenol-based antioxidant comprises at least one selected from the group consisting of a triazine skeleton, a thio skeleton, and a cresol skeleton.   The pressure-sensitive adhesive composition according to claim 1, wherein the ultraviolet absorber is a triazine-based ultraviolet absorber.   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the pressure-sensitive adhesive is an acrylic copolymer.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, further comprising an epoxy-based crosslinking agent.   The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the content of the hindered phenol-based antioxidant is 10.0 parts by mass or less in solid ratio with respect to 100 parts by mass of the pressure-sensitive adhesive. Composition.   The pressure-sensitive adhesive composition according to claim 4 or 5, wherein a content of the epoxy crosslinking agent is 0.001 to 10 parts by mass in solid ratio with respect to 100 parts by mass of the pressure-sensitive adhesive.   It is an adhesive film which consists of an at least 1 base material and an adhesive layer, Comprising: The adhesive film in which the said adhesive layer contains the adhesive composition as described in any one of Claims 1-6.   It is an adhesive film formed by laminating a first release paper, an adhesive layer, and a second release paper in this order, and the adhesive layer is according to any one of claims 1 to 7. An adhesive film comprising the pressure-sensitive adhesive composition.   Use of the adhesive film of Claim 7 or 8 in a transparent substrate bonding use.